A multi-centre, randomized, placebo controlled, trial. Participants at high-risk for vascular events from the network of INTER- CHF will be randomized to inactivated influenza vaccine or placebo and followed prospectively over three influenza seasons. 3,500 participants will be enrolled prior to influenza season, randomized to either influenza vaccine or saline placebo, either of which they will receive annually for three years and then followed over each of the influenza seasons.